A judge in Phoenix has ordered a new trial for a California divorce attorney accused of killing his stepdaughter's husband, finding the evidence didn't support a jury's guilty verdict against the lawyer.

Court officials on Thursday released the ruling by Judge Karen Mullins of Maricopa County Superior Court in the case of Robert Fischer, 54, of Irvine.

County Attorney Bill Montgomery said he was dismayed by the decision and that his office might appeal.

"It's very rare, so it was somewhat surprising," he said. "We give juries great deference in their assessment of facts."

A jury in December convicted Fischer of second-degree murder in the Dec. 30, 2010, shooting death of Norman "Lee" Radder, 49, at the home of Radder and his family in Queen Creek, southeast of Phoenix.

Fischer was visiting the family when Radder died of a single shot from Fischer's handgun into Radder's right eye after an evening of drinking. Authorities contended Radder's death was staged as a suicide.

However, Mullins ruled there was no evidence Fischer pulled the trigger.

"The absence of the defendant's DNA and fingerprints on the gun means it is highly improbable that the defendant fired the gun," Mullins said in her ruling.

Meanwhile, there was DNA evidence indicating Radder had handled the gun, including its magazine, she said.

"This evidence alone requires the court to conclude that is reasonable doubt that the defendant is guilty of second-degree murder," Mullins said.

The physical evidence from the home established only that Fischer was seated near Radder, according to the judge. And an investigator's conclusion that Fischer "staged the scene by manipulating (Radder's) body is not supported by the physical evidence, lacks credibility and is sheer speculation," she said.

Mullins canceled a sentencing that had been set Friday for Fischer, and instead scheduled a hearing to consider setting terms for his release on bond.

Radder lived in Orange County for several years and published a magazine for dirt bike enthusiasts.